Abstract
Digital health interventions (DHIs) offer scalable, accessible approaches to promote healthy sleep in adolescents and to prevent or treat poor sleep and insomnia. Given the high prevalence of sleep problems and their bidirectional links with mental health, this systematic review and meta-analysis examined the effectiveness and active components of DHIs for adolescent sleep. We searched six databases, which included 18 randomised controlled trials (RCTs). Eligible participants were aged 10-24 years. Eighteen RCTs (N = 13,296; mean age 19.0; 71% female) met inclusion criteria: ten evaluated digital cognitive behavioral therapy for insomnia (dCBT-I) and eight targeted sleep promotion (education, hygiene, or holistic programs). Most DHIs were unguided (55.5%) or provided minimal online support (33.3%). Pooled analyses showed that dCBT-I significantly reduced insomnia severity (SMD = -3.32, 95% CI - 5.09 to -1.56) and modestly improved sleep quality (SMD = -0.32, 95% CI - 0.53 to -0.11), with secondary benefits for mental health outcomes. Educational and lifestyle interventions yielded mixed effects. Active components included cognitive restructuring, mindfulness, stimulus control, and sleep restriction. dCBT-I appears most beneficial for adolescents with insomnia or poor sleep. Future research should refine digital delivery, ensure intervention fidelity, and clarify which active ingredients drive sustained improvements in sleep and mental health.